The United Kingdom must offer solutions on how to settle its border with Ireland and insisted it was not up to the European Union to offer compromises, the EU's top Brexit negotiator has said.

Michel Barnier told a conference on Monday that London would need to provide clear proposals soon if they were to find a way for the UK to leave the EU but still have a transparent, open border with Ireland.

He said "those who wanted Brexit must offer solutions".

The EU wants "sufficient progress" on the Irish issue, the rights of EU citizens remaining in Britain and the outstanding bill Britain must pay before the negotiations can move to future relations next month, he said.